Dodge RD200 A/C Clutch Cycle Switch Guide (1979-1980)
Get your classic Dodge truck's air conditioning blowing cold again by troubleshooting and replacing the A/C clutch cycle switch.
- A bad A/C clutch cycle switch is a very common reason for A/C failure on a 1979-1980 Dodge RD200.
- Symptoms include warm air, intermittent cooling, or the compressor clutch not engaging at all.
- WARNING: Your truck may not have a Schrader valve under the switch, requiring a full system evacuation and recharge for replacement.
- Four Seasons is the primary aftermarket brand available, offering an affordable replacement part.
Is Your RD200's A/C Blowing Warm? It Could Be This Switch.
If the air conditioning in your 1979-1980 Dodge RD200 isn't working, a faulty A/C clutch cycle switch is a common suspect. This component is one of the most frequent failure points in an automotive A/C system because of the constant on-and-off cycling it performs. Before assuming your compressor is bad or that you have a major refrigerant leak, it's worth checking this simple switch.
Symptoms of a Failing A/C Clutch Cycle Switch
When the cycle switch goes bad, it will give you clear signs. Look out for these common symptoms in your truck:
- A/C Blows Warm Air: The most obvious symptom is a complete lack of cold air from the vents. A failed switch won't allow the compressor to engage, so the cooling process never starts.
- Intermittent Cooling: The A/C might work sometimes but not others, or cycle on and off more frequently than usual. This can happen when the switch's internal contacts are worn and making a poor connection.
- Compressor Clutch Won't Engage: Pop the hood and have a friend turn the A/C on. You should hear a distinct "click" as the outer part of the A/C compressor pulley (the clutch) engages and starts spinning with the pulley. If it doesn't move at all, the cycle switch may not be sending the signal to turn on.
CRITICAL REPLACEMENT WARNING
Before you unscrew the old switch, you must verify if there is a Schrader valve underneath it. Some older Dodge trucks from this era do NOT have a Schrader valve under the pressure switch. If you unscrew a switch without a valve, all the refrigerant in the system will escape into the atmosphere. This requires a full evacuation and recharge of the A/C system by a professional with the proper equipment. If a valve is present, you can swap the switch without losing refrigerant. Always assume there is no valve until you can confirm otherwise.
Choosing the Right Aftermarket Part
For a vehicle like the 1979-1980 RD200, finding new original equipment (OEM) parts is nearly impossible. The aftermarket is your only realistic source for a new A/C clutch cycle switch.
- Four Seasons: This is the primary brand available for your truck. Four Seasons has been making aftermarket A/C parts for a very long time. While reviews on their more complex parts like compressors can be mixed, their switches and sensors are generally considered a reliable and affordable option for getting an older A/C system working again. Given the limited options, a new Four Seasons switch is the go-to choice.
| Part Type | Our Price Range | Notes |
|---|---|---|
| New Aftermarket (Four Seasons) | $38.72 | The most common and reliable option available. |
| New OEM | Not Available | Original parts for this truck are no longer manufactured. |
| Used OEM | Varies | Risky due to age and unknown condition. Not recommended. |
Pro Tip: Check the Basics First
Before replacing the switch, make sure your A/C system has a proper refrigerant charge. A low refrigerant level will also cause the low-pressure switch to keep the compressor from turning on as a safety measure. If your system is low, you have a leak that needs to be fixed first.
Frequently Asked Questions (FAQ)
Where is the A/C clutch cycle switch located on my RD200?
The A/C clutch cycle switch is typically a small, sensor-like part screwed into the A/C accumulator (a metal can-shaped component on the low-pressure side of the system). Look for it along the A/C lines in the engine bay, often near the firewall on the passenger side.
Can I replace the A/C clutch cycle switch myself?
Maybe. If your truck has a Schrader valve under the switch, the job is very easy and just requires a wrench. However, if there is no valve, the entire A/C system must be professionally evacuated and recharged, making it a job for a qualified mechanic. Because of this uncertainty, DIY replacement is only for those who can verify the valve's presence and are prepared to take it to a shop if needed.
Are there any recalls for the A/C system on my 1979-1980 Dodge truck?
Searches of the National Highway Traffic Safety Administration (NHTSA) database show no recalls specifically for the A/C clutch cycle switch on this vehicle. Any failure is due to the age and normal wear of the part.
Will replacing the switch fix my A/C?
If the switch is the faulty component, then yes. However, other issues like low refrigerant, a bad compressor clutch, a blown fuse, or other electrical problems can also cause the A/C to fail. The switch is an inexpensive and common failure point, making it a good place to start your diagnosis.
Technical Specifications
System Mounted Preset Cycling Temperature Switch
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.